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TO ALI, WHOM IT MAY CONCERN Be it known that I, ADDISON C. FLETCHER, of the city, county, and State of New York, have invented a new. and useful improvementl in Apparatus for Heating Air, to be supplied to furnaces, or for other. purposes, also applicable to the condensa-tion of the exhaust steam from an engine; and I do hereby declare that the following is a fulll` clear, and exactdescription of the same, reference being had tothe accompanying drawings, forming part of this specification, in which- Figure 1 is a vcrtical'scctional view, illustrating the application of my invention to-thc heating of air for the supply of the furnace of a steam boiler by the wast-e heat in the s1nokc-stack or chimney.

.Fig-nrc 2 is a horizontal section of the smoke-stack and nir-hcating apparatus, in the plane indicated by the line :l: a: of fig. 1. v

Figure 5J is a vertical section,'illustrating the application of my invention to the condensation of the exhaust steam from an engine. i i

Similar letters of reference indicate corresponding parts in the several figures. This invention consist in a novel arrangement. of an air-heating passage within thc smoke pipe, chimney, or upright Hue of a stcamhoile'r or other furnace, or within the'exhaust-steam pipe of au engine, in connection with an air-jacket surrounding such pipe, chimney, orflluc, whereby air drawn or forced through the said passage and jacketis etl'ectually heated by the waste heat of the escaping gaseous or fuliginous products of combustion or exhaust steam, for thc promotion of combustion in the boiler-or other furnace, and whereby also, in the case of the application of thc invention to anexhuust-steam pipe, the condensation of steam for'the production of a partial vacuum, and the saving of the water of condensation at a high temperature, for return to the boiler', or for any other use, is effected. t

To enable others skilled in the art to apply lay-intention to use, I will proceed to describe it, with reference to the drawings.

A (fig. l) is a steam boiler, and is its furnace. C (figs. 1 and is the smoke pipe or chimney. D- is the-v air-jacket, surrounding thc smoke pipe or chimney concentrically, made of sheet metal orothcr material, and' closed ut the bottom, but having openings a a, at equal intervals apart, all around it near the top, for the entrance of air. E is the air-passage, which constitutes the principal feature ofthe invention, formed of sheet metal, and extending diametrically or otherwise transversely across thc smoke pipe `or chimney, the whole or nearly thc whole length thereof, and communicating along its whole or nearly its whole length with the interior of theiair-jacker l), on opposite sides ofthe smoke pipe or chimney. lhe lower part of the jacket is connected on opposite sides, and opposite to the openings of the-passage E, by two branch pipes g g, with a pipe, G, lead ing to the inlet ypipe or eye of a rotary fan blow'er, l", the outlet or discharrfe pipe of which is supposed to lenti to the boiler furnace.

The operation of the example of'niy apparatus represented in figs. 1 and is as follows: The tire having been well startethand the blowerbeingin action, thc'blower tends to produce a partial vacuum in the airjacket D and air'passage E, and'coldair, from outside of the jacket D rushes in to fill, this vacuum through the openings a a. This air, circulating through the jacket and passage E, as shown in black arrows in lig. 1, on its way to the blower is heated by Contact with and radiation from the heated exterior of the smoke pipe or chimney, and also by contact with and radiation from the interior surface of the passage E. This passage being surrounded by the het gaseous and fuliginous products of combustion, ascending through the smoke pipe or chimney, constitutes, in proportion to its area, the most effective heating surface. The air having been thus heated, is drawn into the blower, and driven therefrom into the furnace, either above and helen', or both above and below the grate. y l

In the application of the invention to the exhaust pipe of a steam engine, the exhaust pipe I is arranged as shown in 3, on the top of a hot well,J, and open at the bottom thereto; and the jacket D,Itransverse air-passagc E, and air pipes Cry g, are arranged in the same manner, in relation with the said pipe d, as they arc in relation with the smoke pipcor chimney C, and the airis caused to circulate through the said jacket,

passage, and air pipes, in the same manner as through those applied to the smoke pipe or chimney, by means ot".V

a blower connected with the pipo G; and the nir, thus heated in the jacket and air-passage, is driven by the.

blower to the furnace, orto wherever else it is to be utilized.. The exhaust steam, entering the upper part of the hot well, cireulating'upward within the exhaust pipe, is in part condensed by the -heat abstractedA by the air; 'and the water of condensation, trickling down the interior` surfaeesof the jacket and exterior of the airpa-ssage E, runs into the hot well, whence it is drawn oil', at a near-lv boiling temperature, to be supplied to the boiler, or for any other purpose.

Instead of a single air-passage, E, extending transversely through the smoke pipe or Chimney, or through the exhaust pipe, a series ofuir-pas'sages, arranged one above another, may be employed as an equivalent, such passages extending in the same manner transversely through the pipe or chimney, and communicating withlthe jacket in the same ina-nner, on opposite sides thereof. And instead of the said single air-passage, there may be two or vmore air-passages, crossing each other at right angles, each vcommunioating with the jacket on opposite sides of the pipe or chimney. The air, instead of being drawn by the blower through the said air-passage, may be driven or forced through them by a blower, the outlet of which communicates with the inlet openings of the jacket. The relative positions of the inlet and outlet openings ofthe jacket D may be '-reversed, the inlet being in that ease at the bottom, and the outlet at the top.

What I claim as my invention, and desire to secure by Letters Patent, lis

The air-passage or passages E, extending transversely across and through thc smoke pipe, chimney flue, or exhaust pipe, for the whole or nearly the whole length of, and in combination with, the jacket D, surrounding the said pipe, chimney, or lue, substantially as and for the purpose herein speeied.

ADDISON C. FLETCHER.

Witnesses:

SAM. L. HARRIS, Cuirs. HiGeINs. 

